Method and device for distributing powder material

ABSTRACT

Described is an additive manufacturing apparatus for additive manufacturing of three dimensional objects, said apparatus comprises a powder distribution unit movable across a build area for applying a layer of powder material thereon and a solidification device for selectively solidifying the applied powder layer at positions corresponding to a cross section of the object to be manufactured. Said powder distribution unit comprises at least a first and a second powder distributors essentially in parallel with each other and extending in a first direction, said first and second powder distributors are arranged to be adjustably spaced apart in a second direction transversely to said first direction which second direction is essentially in parallel with the direction of movement of said powder distribution unit over said build area.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of Ser. No. 16/266,729, filed Feb. 4,2019, which claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/649,750, filed on Mar. 29, 2018; the contentsof which as are hereby incorporated by reference in their entirety.

BACKGROUND Related Field

The invention relates to a powder distributing unit and a method fordistributing powder material in an additive manufacturing apparatus.

Description of Related Art

Freeform fabrication or additive manufacturing (AM) using electron beammelting (EBM) or laser beam melting is a method for forming a solidthree-dimensional article from a powder. The three-dimensional articleis formed layer by layer by successive fusion of selected areas ofpowder layers, which selected areas correspond to successive layers ofthe three-dimensional article. A layer of powder, such as metal powder,is deposited on a build area and an electron beam or a laser beam isused to selectively melt the powder layer of the build area. The meltedmaterial fuses with under-laying layers and solidifies to form the toplayer of the solid three-dimensional article. A further layer of powderis deposited onto the previous layer, and the electron or laser beam isused to selectively melt the further powder layer of the build area. Themelted material solidifies and form another solid layer fused onto theprevious solid layer. This process is repeated for multiple layers untilthe desired 3D geometry of the article is achieved.

An apparatus for forming such a three-dimensional article has a buildtable onto which the three-dimensional article is to be formed, a powderdistributor device for delivering powder to the build table (build area)for the formation of the powder layers and an electron beam source or alaser beam source for providing the energy beam used for melting thepowder. The build table is arranged in a build tank which in turn isarranged in a build chamber formed by a casing. When using EBM, thebuild chamber is a vacuum chamber.

A powder layer is created by first distributing a predetermined amountof powder onto the build table by a powder distributor. Thereafter thepowder distributor may again be moved over the build table one orseveral times in order to even out any powder surface irregularities. Aneven top surface of the powder material, which is to be fused, isimportant for a finished three-dimensional article with high mechanicalstrength and an outer dimension resembling with the cad file from whichthe three-dimensional article is created. However, since a normalthree-dimensional article is made up of thousands of individual layers,such repeated powder distribution takes a considerably amount of thetotal build time which is a problem. Secondly, as the build time isincreased it may be necessary to increase the heat input in order tomaintain a predetermined temperature interval for the build.

BRIEF SUMMARY

An objective of the invention is to provide a method for powderdistribution in an additive manufacturing apparatus which provides foran even top surface irrespective of the powder material and the powderthickness which is to be formed which takes shorter time compared toprior art solutions.

The object is achieved by an additive manufacturing apparatus foradditive manufacturing of three dimensional objects by selectivelysolidifying a powder material layer by layer, wherein the apparatuscomprises a powder distribution unit movable across a build area forapplying a layer of powder material thereon and a solidification devicefor selectively solidifying the applied powder layer at positionscorresponding to a cross section of the object to be manufactured and acontrol unit adapted to repeat the steps of applying and selectivelysolidifying until the object is completed, wherein the powderdistribution unit comprises a first and a second powder distributorsessentially in parallel with each other and extending in a firstdirection, the first and second powder distributors are arranged to beadjustably spaced apart in a second direction transversely to the firstdirection which second direction is essentially in parallel with thedirection of movement of the powder distribution unit over the buildarea.

An exemplary advantage of various embodiments of the present inventionis that the distance between at least two powder distributors may bevaried depending on different powder application circumstances such asthe powder material, the powder layer thickness, the temperature ontowhich the powder layer are to be applied and/or the powder particledistribution. The freedom to vary the distance between at least topowder distributors depending on the physical requirements of the powdermaterial to be applied at the same time as minimizing its physicaldimension at its end positions means that the inventive design willfulfill as smooth powder layer application as possible without enlargingthe physical dimension of the additive manufacturing machine as suchcompared to prior art design.

In another example embodiment of the present invention the first powderdistributor is arranged to be movable across the build areaindependently of the second powder distributor. An exemplary advantageof having multiple powder distributors moving independently of eachother will result in more efficient powder application compared to priorart.

In still another example embodiment of the present invention the firstpowder distributor is adapted to move across the build area with a firstspeed and the second powder distributor is arranged to move across thebuild area with a second speed. An exemplary advantage of moving thefirst and second powder distributors at different speeds may improve thefinal quality of the top surface of the powder layer. Different amountof powder material pushed in front of a powder distributor may needdifferent speeds in order to create as smooth surface as possible. Thatmeans that a speed of a single powder distributor may vary along itsstroke of powder application since the amount of powder is constantlydecreasing.

In yet another example embodiment of the present invention the firstpowder distributor is arranged to be moving across the build area at afirst distance from the build area and the second powder distributor isarranged to be moving across the build area at a second distance fromthe build area. An exemplary advantage of arranging a first and secondpowder distributor at different height compared to each other is thatone may steer how much powder material the first and second powderdistributor is to pick up and individually apply onto the build area.

In still another example embodiment of the present invention the firstpowder distributor is having a first shape and the second powderdistributor is having a second shape. An exemplary advantage of havingdifferent shapes of the different powder distributors is that theleading powder distributor may be the one that provides powder materialonto the build area and the trailing powder distributor may be the onethat smooths out the top surface already applied by the first powderdistributor.

In still another example embodiment the first and second powderdistributors are arranged to be spaced apart with a first distance whenat rest and a second distance when the first and second powderdistributors are moving. An exemplary advantage of this embodiment isthat the additive manufacturing apparatus may be manufactured compactalthough the separation between the powder distributors may be largewhen moving if the first distance is smaller than the second distance.

In another aspect of the invention it is provided a method for additivemanufacturing of three-dimensional objects by selectively solidifying apowder material layer by layer, the method comprising the steps of:applying a layer of powder material within a build area by means of apowder distribution unit moving across the build area, wherein thepowder distribution unit comprises a first powder distributor and asecond powder distributor essentially in parallel with each other andextending in a first direction, selectively solidifying the appliedpowder material at positions corresponding to a cross-section of theobject to be manufactured, by means of a solidification device,repeating the steps of applying and selectively solidifying until theobject is completed, the method further comprising the steps of movingthe first and second powder distributors across the build area in asecond direction transversely to the first direction, and varying adistance between the first and second powder distributors at least onceduring the manufacturing of the three-dimensional object.

An exemplary advantage of this embodiment is that a plurality of powderdistributors may be arranged at suitable distance between each otherdepending on the particular additive manufacturing process step.

In another example embodiment the first and second powder distributorsare moving independently of each other. An exemplary advantage of atleast this embodiment is that each and every powder distributor may becontrolled individually at each and every position and stage of additivemanufacturing process.

In another example embodiment the first and second powder distributorsare spaced apart with a first distance when at rest and a seconddistance when moving. An exemplary advantage of at least this embodimentis that the powder distributors may be packed closely together when notin use for minimizing it space consumption whereas when in use itsindividual distance between each other may be enlarged for applying thepowder material as efficient and as good as possible.

In still another example embodiment of the present invention the firstpowder distributor may be moving at a first speed and the second powderdistributor may be moving at a second speed. An exemplary advantage ofat least this embodiment is that a leading and a trailing powderdistributor may have different functionality, i.e., applying powder andsmoothening out a top surface of an already applied powder layer, andthis may require different speed of the first and second powderdistributors in order to reach optimal flatness of the powder layer.

In still another example embodiment of the present invention the firstand second powder distributors may be moving at different distance fromthe build area. An exemplary advantage of at least this embodiment isthat the top surface of the powder layer may be smoother if a trailingpowder distributor is closer to the build area than the leading powderdistributor.

Further advantages and advantageous features of the invention aredisclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

With reference to the appended drawings, below follows a more detaileddescription of embodiments of the invention cited as examples.

In the drawings:

FIG. 1 is a schematic view of an AM apparatus having the inventivepowder distribution unit according to the present invention,

FIG. 2A is a perspective top view showing the build table and theinventive powder distribution unit in a first position,

FIG. 2B is a perspective top view showing the build table and theinventive powder distribution unit in a second position,

FIG. 3 is a block diagram of an exemplary system according to variousembodiments,

FIG. 4 is a schematic block diagram of an exemplary server according tovarious embodiments, and

FIG. 5 is a schematic block diagram of an exemplary mobile deviceaccording to various embodiments.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various embodiments of the present invention will now be described morefully hereinafter with reference to the accompanying drawings, in whichsome, but not all embodiments of the invention are shown. Indeed,embodiments of the invention may be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Unless otherwise defined, alltechnical and scientific terms used herein have the same meaning ascommonly known and understood by one of ordinary skill in the art towhich the invention relates. The term “or” is used herein in both thealternative and conjunctive sense, unless otherwise indicated. Likenumbers refer to like elements throughout.

Still further, to facilitate the understanding of this invention, anumber of terms are defined below. Terms defined herein have meanings ascommonly understood by a person of ordinary skill in the areas relevantto the present invention. Terms such as “a”, “an” and “the” are notintended to refer to only a singular entity, but include the generalclass of which a specific example may be used for illustration. Theterminology herein is used to describe specific embodiments of theinvention, but their usage does not delimit the invention, except asoutlined in the claims.

The term “three-dimensional structures” and the like as used hereinrefer generally to intended or actually fabricated three-dimensionalconfigurations (e.g., of structural material or materials) that areintended to be used for a particular purpose. Such structures, etc. may,for example, be designed with the aid of a three-dimensional CAD system.

The term “electron beam” as used herein in various embodiments refers toany charged particle beam. The sources of charged particle beam caninclude an electron gun, a linear accelerator and so on.

FIG. 1 shows an AM apparatus 1 for forming a three-dimensional article 2layer by layer by successive fusion of selected areas of a powderlayers, which selected areas correspond to successive layers of thethree-dimensional article. The apparatus 1 comprises a build chamber 4,and a build tank 5 arranged inside the build chamber 4.

Further, the apparatus 1 comprises a powder tank 14, a powderdistribution unit 28 and a build table 9 for receiving powder from thepowder distribution unit 28. The build table 9 is arranged inside thebuild tank 5. The build table 9 has a top surface 10 for receivingpowder from the powder distribution unit 28. The top surface 10 of thebuild table 9 is preferably flat and horizontal and is faced upwardly ina vertical direction.

The build table 9 comprises means for movement of the build table 9relative to the build tank 5 in the vertical direction, such as a servomotor equipped with a gear, adjusting screws, etc. The powderdistribution unit 28 is arranged to lay down a thin layer of the powdermaterial on the build table 9 or powder bed 12 in the build tank 5.During a work cycle the build table 9 will be lowered for maintainingthe position of the top surface of the powder bed relative to the buildtank 5 when adding powder layers to the powder bed 12.

The apparatus 1 has an energy beam source 6 arranged for creating anenergy beam. The energy beam is used for melting the selected areas ofthe powder. The energy beam is scanned over the surface of the currentpowder layer for melting the selected areas. The selected areas of eachlayer can be based on a model dividing the article to be manufactured insuccessive layers or slices. The model may be a computer model generatedby a CAD (Computer Aided Design) tool.

In the example embodiment illustrated in FIG. 1 , the energy beam source6 is an electron beam source. The electron beam source can be designedin a way well known to the person skilled in the art. The electron beamsource may have an electron gun with an emitter electrode which isconnected to a high voltage circuit and a current source foraccelerating electrons and releasing electrons from the emitterelectrode. These electrons form the electron beam. The electron beamsource has also focusing coils and deflection coils 7 for directing theelectron beam to various positions of the build layer surface.

The build chamber 4 can be arranged for maintaining a vacuum environmentby means of a vacuum system, which may comprise a turbomolecular pump, ascroll pump, an ion pump and one or more valves. Such a vacuum system isknown to the person skilled in the art and is not further described orillustrated herein.

In another embodiment of the apparatus, any other suitable energy beamsource can be used. For example, a laser beam source. The laser beamsource can be designed in a way well known to the person skilled in theart. The laser beam source may have a laser emitter for emittingphotons. These photons form the laser beam. The laser beam source hasalso focusing units and deflection units for directing the laser beam tovarious positions of the build layer surface. The focusing units cancomprise lenses and the deflection units can comprise mirrors.

The build tank 5 may be a cylinder and the build table 9 is arrangedinside the cylinder. The cylinder is a body having a cylinder-shapedcavity for receiving the build table 9, preferably a substantiallycircular cylinder with an inner diameter. Optionally, the outerperipheral surface of the cylinder can also be circular cylinder-shaped.The build table 9 is displaceable relative to the cylinder in an axialdirection denoted by arrow A.

Powder material to be distributed as powder layers onto the build table9 in the build tank 5 is stored in a powder tank 14. The powderdistribution unit 28 picks up a predetermined amount of powder from thepowder tank and distributes the powder onto the build table 9 in thebuild tank 5. The predetermined amount of powder picked up by the powderdistribution unit 28 is determined by the amount a powder raised above apowder table 20. The predetermined amount of powder is regulated by alevel of a powder tank table 18.

A powder layer thickness of a new powder layer in the build tank 5 isdetermined by how much the build table 9 is lowered down into the buildtank 5 relative to the powder table 20.

An area of the build table 9 may be equal to an area of the powder tanktable 18.

The powder distribution unit 28 comprises in an example embodimentaccording to the present invention of a first 210 and a second 220powder distributor. In other example embodiments the powder distributionunit 28 may comprise 3 or more powder distributors. The first and secondpowder distributors 210 and 220 respectively are movable independentlyof each other. In at least one position, which may be the idlingposition where the powder distribution unit is at rest, the first 210and second 220 powder distributors are separated by a first distance D1.When the powder distribution unit 28 is distributing powder on top ofthe build table 9 the first powder distributor 210 and the second powderdistributor 220 may be separated by a second distance D2. The seconddistance D2 may be larger than the first distance D1. The distancebetween the first 210 and second 220 powder distributors may vary alongits path from one side to the other. In a first example embodiment thefirst and second powder distributors 210, 220 may be separated by thefirst distance D1 when picking up powder from the powder tank and thendistribution at least a portion of the powder onto the build table 9with a second distance D2 between the first and second powderdistributors 210, 220.

In an alternative embodiment, the first end second powder distributors210, 220 may be separated by a third distance when picking up powderfrom the powder tank, where the third distance is in between the firstdistance D1 and the second distance D2. In yet another exampleembodiment at least one of the powder distributors 210, 220 in thepowder distribution unit 28 may be picking up powder material from thepowder tank 14 while at least one other powder distributor in the powderdistributor unit is at rest, i.e., the second powder distributor 220 maypass the powder tank 14 before the first powder distributor 210 startmoving.

In another example embodiment the second powder distributor 220 ispassing over the powder tank 14 with the powder tank table at a firstposition. After the second powder distributor have passed over thepowder tank the first powder distributor 210 is passing over the powdertank with the powder tank table at a second position. The secondposition of the powder tank table 18 is closer to the powder table 20than the first position of the powder tank table 18 which may result inpowder removal from the powder tank by both the first and second powderdistributor. This in turn will result in powder material applicationonto the build table 9 by the first and the second powder distributors.

In still another example embodiment the first and second powderdistributors 210, 220 having the second distance D2 in at least oneposition over the powder tank 14 while picking up powder from it. Thepowder tank table 18 may be at rest or moving upwards while picking uppowder from it. If the powder tank table is at rest only the secondpowder distributor 220, i.e., the one passing over the powder tank 14first, will pick up powder and pushing the powder in front of it. If thepowder tank is moving upwards not only the leading powder distributor,220 in this case, will pick up powder by also the trailing powderdistributor, 210 in this case, will pick up powder. In the latter casepowder may be distributed over the build table from the first 220 andthe second 210 powder distributors.

The distance between the first powder distributor 210 and the secondpowder distributor 220 may depend on the powder material to bedistributed, the powder thickness to be distributed, the powder particledistribution of the powder material to be distributed and/or the averagetemperature of the top surface onto which the powder layer is to bedistributed. For instance, a thicker powder layer may require a largerdistance between the first and second powder distributors 210, 220 whenapplying the powder onto the build table 9 compared to a thinner powderlayer. A powder material having a high viscosity may need a largerseparation between the first and second powder distributor when applyingthe powder layer onto the build table compared to a powder material witha lower viscosity. The reason for needing a larger separation forthicker powder layers and higher viscosity is that powder particles tendto interfere with each other. This means that if the powder distributorsare too close to each other they tend to disturb one another so that theresulting powder layer smoothness will be destroyed. Increasing theseparation between the first and second powder distributors willeliminate the interference/crosstalk situation and the resulting powderlayer smoothness will be improved.

A control unit 8 may control the movement of the powder distributionunit 28, the powder tank table 18, the build table 9, the high energybeam 6 and the focus and deflection units 7 for the high energy beam.The control unit 8 may also comprise the scheme for steering the highenergy beam in order to manufacture the three-dimensional articleaccording to CAD data.

FIGS. 2A and 2B depict perspective views of another example embodimentof the present invention. In FIG. 2A it is illustrated a first powderdistributor 210, a second powder distributor 220, a build tank 240, afirst powder tank 230, a second powder tank 250 a high energy beamsource 200 and a high energy beam 270. In FIG. 2A the first and secondpowder distributors 210, 220 are at rest to the left of the first powdertank 230. The distance between the first and second powder distributorswhen at rest are denoted by distance D1. The energy beam source 200 areheating and/or melting the powder material in the build tank 240 in FIG.2A.

In FIG. 2B, the first and second powder distributors are applying thepowder material picked up from the first powder tank 230 onto a buildtable in the build tank 240. The separation between the first and secondpowder distributors while applying the powder layer onto the build tableare denoted by D2. D2 is larger than D1. In FIG. 2B the high energy beamsource may heat the powder material while providing it onto the buildtable.

In a first example embodiment the distance D1 is 0-5 mm and the distanceD2 is 20-40 mm.

In all example embodiments the first and second powder distributors moveindependently of each other. This means that the first and second powderdistributor may start to move at different time. The first and secondpowder distributor may move at different speeds. The first powderdistributor may move above the powder table at a first distance whilethe second powder distributor move above the powder table at a seconddistance. The first and second powder distributors may have equal shapeor different shapes.

In another aspect of the invention it is provided a program elementconfigured and arranged when executed on a computer to implement amethod as described herein. The program element may be installed in acomputer readable storage medium. The computer readable storage mediummay be any one of the control units described elsewhere herein oranother and separate control unit, as may be desirable. The computerreadable storage medium and the program element, which may comprisecomputer-readable program code portions embodied therein, may further becontained within a non-transitory computer program product. Furtherdetails regarding these features and configurations are provided, inturn, below.

As mentioned, various embodiments of the present invention may beimplemented in various ways, including as non-transitory computerprogram products. A computer program product may include anon-transitory computer-readable storage medium storing applications,programs, program modules, scripts, source code, program code, objectcode, byte code, compiled code, interpreted code, machine code,executable instructions, and/or the like (also referred to herein asexecutable instructions, instructions for execution, program code,and/or similar terms used herein interchangeably). Such non-transitorycomputer-readable storage media include all computer-readable media(including volatile and non-volatile media).

In one embodiment, a non-volatile computer-readable storage medium mayinclude a floppy disk, flexible disk, hard disk, solid-state storage(SSS) (e.g., a solid state drive (SSD), solid state card (SSC), solidstate module (SSM)), enterprise flash drive, magnetic tape, or any othernon-transitory magnetic medium, and/or the like. A non-volatilecomputer-readable storage medium may also include a punch card, papertape, optical mark sheet (or any other physical medium with patterns ofholes or other optically recognizable indicia), compact disc read onlymemory (CD-ROM), compact disc compact disc-rewritable (CD-RW), digitalversatile disc (DVD), Blu-ray disc (BD), any other non-transitoryoptical medium, and/or the like. Such a non-volatile computer-readablestorage medium may also include read-only memory (ROM), programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), flashmemory (e.g., Serial, NAND, NOR, and/or the like), multimedia memorycards (MMC), secure digital (SD) memory cards, SmartMedia cards,CompactFlash (CF) cards, Memory Sticks, and/or the like. Further, anon-volatile computer-readable storage medium may also includeconductive-bridging random access memory (CBRAM), phase-change randomaccess memory (PRAM), ferroelectric random-access memory (FeRAM),non-volatile random-access memory (NVRAM), magnetoresistiverandom-access memory (MRAM), resistive random-access memory (RRAM),Silicon-Oxide-Nitride-Oxide-Silicon memory (SONOS), floating junctiongate random access memory (FJG RAM), Millipede memory, racetrack memory,and/or the like.

In one embodiment, a volatile computer-readable storage medium mayinclude random access memory (RAM), dynamic random access memory (DRAM),static random access memory (SRAM), fast page mode dynamic random accessmemory (FPM DRAM), extended data-out dynamic random access memory (EDODRAM), synchronous dynamic random access memory (SDRAM), double datarate synchronous dynamic random access memory (DDR SDRAM), double datarate type two synchronous dynamic random access memory (DDR2 SDRAM),double data rate type three synchronous dynamic random access memory(DDR3 SDRAM), Rambus dynamic random access memory (RDRAM), TwinTransistor RAM (TTRAM), Thyristor RAM (T-RAM), Zero-capacitor (Z-RAM),Rambus in-line memory module (RIMM), dual in-line memory module (DIMM),single in-line memory module (SIMM), video random access memory VRAM,cache memory (including various levels), flash memory, register memory,and/or the like. It will be appreciated that where embodiments aredescribed to use a computer-readable storage medium, other types ofcomputer-readable storage media may be substituted for or used inaddition to the computer-readable storage media described above.

As should be appreciated, various embodiments of the present inventionmay also be implemented as methods, apparatus, systems, computingdevices, computing entities, and/or the like, as have been describedelsewhere herein. As such, embodiments of the present invention may takethe form of an apparatus, system, computing device, computing entity,and/or the like executing instructions stored on a computer-readablestorage medium to perform certain steps or operations. However,embodiments of the present invention may also take the form of anentirely hardware embodiment performing certain steps or operations.

Various embodiments are described below with reference to block diagramsand flowchart illustrations of apparatuses, methods, systems, andcomputer program products. It should be understood that each block ofany of the block diagrams and flowchart illustrations, respectively, maybe implemented in part by computer program instructions, e.g., aslogical steps or operations executing on a processor in a computingsystem. These computer program instructions may be loaded onto acomputer, such as a special purpose computer or other programmable dataprocessing apparatus to produce a specifically-configured machine, suchthat the instructions which execute on the computer or otherprogrammable data processing apparatus implement the functions specifiedin the flowchart block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including computer-readableinstructions for implementing the functionality specified in theflowchart block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed on the computeror other programmable apparatus to produce a computer-implementedprocess such that the instructions that execute on the computer or otherprogrammable apparatus provide operations for implementing the functionsspecified in the flowchart block or blocks.

Accordingly, blocks of the block diagrams and flowchart illustrationssupport various combinations for performing the specified functions,combinations of operations for performing the specified functions andprogram instructions for performing the specified functions. It shouldalso be understood that each block of the block diagrams and flowchartillustrations, and combinations of blocks in the block diagrams andflowchart illustrations, could be implemented by special purposehardware-based computer systems that perform the specified functions oroperations, or combinations of special purpose hardware and computerinstructions.

FIG. 3 is a block diagram of an exemplary system 320 that can be used inconjunction with various embodiments of the present invention. In atleast the illustrated embodiment, the system 320 may include one or morecentral computing devices 110, one or more distributed computing devices120, and one or more distributed handheld or mobile devices 300, allconfigured in communication with a central server 1200 (or control unit)via one or more networks 130. While FIG. 3 illustrates the varioussystem entities as separate, standalone entities, the variousembodiments are not limited to this particular architecture.

According to various embodiments of the present invention, the one ormore networks 130 may be capable of supporting communication inaccordance with any one or more of a number of second-generation (2G),2.5G, third-generation (3G), and/or fourth-generation (4G) mobilecommunication protocols, or the like. More particularly, the one or morenetworks 130 may be capable of supporting communication in accordancewith 2G wireless communication protocols IS-136 (TDMA), GSM, and IS-95(CDMA). Also, for example, the one or more networks 130 may be capableof supporting communication in accordance with 2.5G wirelesscommunication protocols GPRS, Enhanced Data GSM Environment (EDGE), orthe like. In addition, for example, the one or more networks 130 may becapable of supporting communication in accordance with 3G wirelesscommunication protocols such as Universal Mobile Telephone System (UMTS)network employing Wideband Code Division Multiple Access (WCDMA) radioaccess technology. Some narrow-band AMPS (NAMPS), as well as TACS,network(s) may also benefit from embodiments of the present invention,as should dual or higher mode mobile stations (e.g., digital/analog orTDMA/CDMA/analog phones). As yet another example, each of the componentsof the system 320 may be configured to communicate with one another inaccordance with techniques such as, for example, radio frequency (RF),Bluetooth™, infrared (IrDA), or any of a number of different wired orwireless networking techniques, including a wired or wireless PersonalArea Network (“PAN”), Local Area Network (“LAN”), Metropolitan AreaNetwork (“MAN”), Wide Area Network (“WAN”), or the like.

Although the device(s) 110-300 are illustrated in FIG. 3 ascommunicating with one another over the same network 130, these devicesmay likewise communicate over multiple, separate networks.

According to one embodiment, in addition to receiving data from theserver 1200, the distributed devices 110, 120, and/or 300 may be furtherconfigured to collect and transmit data on their own. In variousembodiments, the devices 110, 120, and/or 300 may be capable ofreceiving data via one or more input units or devices, such as a keypad,touchpad, barcode scanner, radio frequency identification (RFID) reader,interface card (e.g., modem, etc.) or receiver. The devices 110, 120,and/or 300 may further be capable of storing data to one or morevolatile or non-volatile memory modules, and outputting the data via oneor more output units or devices, for example, by displaying data to theuser operating the device, or by transmitting data, for example over theone or more networks 130.

In various embodiments, the server 1200 includes various systems forperforming one or more functions in accordance with various embodimentsof the present invention, including those more particularly shown anddescribed herein. It should be understood, however, that the server 1200might include a variety of alternative devices for performing one ormore like functions, without departing from the spirit and scope of thepresent invention. For example, at least a portion of the server 1200,in certain embodiments, may be located on the distributed device(s) 110,120, and/or the handheld or mobile device(s) 300, as may be desirablefor particular applications. As will be described in further detailbelow, in at least one embodiment, the handheld or mobile device(s) 300may contain one or more mobile applications 330 which may be configuredso as to provide a user interface for communication with the server1200, all as will be likewise described in further detail below.

FIG. 4 is a schematic diagram of the server 1200 according to variousembodiments. The server 1200 includes a processor 1230 that communicateswith other elements within the server via a system interface or bus1235. Also included in the server 1200 is a display/input device 1250for receiving and displaying data. This display/input device 1250 maybe, for example, a keyboard or pointing device that is used incombination with a monitor. The server 1200 further includes memory1220, which typically includes both read only memory (ROM) 1226 andrandom access memory (RAM) 1222. The server's ROM 1226 is used to storea basic input/output system 1224 (BIOS), containing the basic routinesthat help to transfer information between elements within the server1200. Various ROM and RAM configurations have been previously describedherein.

In addition, the server 1200 includes at least one storage device orprogram storage 210, such as a hard disk drive, a floppy disk drive, aCD Rom drive, or optical disk drive, for storing information on variouscomputer-readable media, such as a hard disk, a removable magnetic disk,or a CD-ROM disk. As will be appreciated by one of ordinary skill in theart, each of these storage devices 1210 are connected to the system bus1235 by an appropriate interface. The storage devices 1210 and theirassociated computer-readable media provide nonvolatile storage for apersonal computer. As will be appreciated by one of ordinary skill inthe art, the computer-readable media described above could be replacedby any other type of computer-readable media known in the art. Suchmedia include, for example, magnetic cassettes, flash memory cards,digital video disks, and Bernoulli cartridges.

Although not shown, according to an embodiment, the storage device 1210and/or memory of the server 1200 may further provide the functions of adata storage device, which may store historical and/or current deliverydata and delivery conditions that may be accessed by the server 1200. Inthis regard, the storage device 1210 may comprise one or more databases.The term “database” refers to a structured collection of records or datathat is stored in a computer system, such as via a relational database,hierarchical database, or network database and as such, should not beconstrued in a limiting fashion.

A number of program modules (e.g., exemplary modules 400-700)comprising, for example, one or more computer-readable program codeportions executable by the processor 1230, may be stored by the variousstorage devices 1210 and within RAM 1222. Such program modules may alsoinclude an operating system 1280. In these and other embodiments, thevarious modules 400, 500, 600, 700 control certain aspects of theoperation of the server 1200 with the assistance of the processor 1230and operating system 1280. In still other embodiments, it should beunderstood that one or more additional and/or alternative modules mayalso be provided, without departing from the scope and nature of thepresent invention.

In various embodiments, the program modules 400, 500, 600, 700 areexecuted by the server 1200 and are configured to generate one or moregraphical user interfaces, reports, instructions, and/ornotifications/alerts, all accessible and/or transmittable to varioususers of the system 320. In certain embodiments, the user interfaces,reports, instructions, and/or notifications/alerts may be accessible viaone or more networks 130, which may include the Internet or otherfeasible communications network, as previously discussed.

In various embodiments, it should also be understood that one or more ofthe modules 400, 500, 600, 700 may be alternatively and/or additionally(e.g., in duplicate) stored locally on one or more of the devices 110,120, and/or 300 and may be executed by one or more processors of thesame. According to various embodiments, the modules 400, 500, 600, 700may send data to, receive data from, and utilize data contained in oneor more databases, which may be comprised of one or more separate,linked and/or networked databases.

Also located within the server 1200 is a network interface 1260 forinterfacing and communicating with other elements of the one or morenetworks 130. It will be appreciated by one of ordinary skill in the artthat one or more of the server 1200 components may be locatedgeographically remotely from other server components. Furthermore, oneor more of the server 1200 components may be combined, and/or additionalcomponents performing functions described herein may also be included inthe server.

While the foregoing describes a single processor 1230, as one ofordinary skill in the art will recognize, the server 1200 may comprisemultiple processors operating in conjunction with one another to performthe functionality described herein. In addition to the memory 1220, theprocessor 1230 can also be connected to at least one interface or othermeans for displaying, transmitting and/or receiving data, content or thelike. In this regard, the interface(s) can include at least onecommunication interface or other means for transmitting and/or receivingdata, content or the like, as well as at least one user interface thatcan include a display and/or a user input interface, as will bedescribed in further detail below. The user input interface, in turn,can comprise any of a number of devices allowing the entity to receivedata from a user, such as a keypad, a touch display, a joystick or otherinput device.

Still further, while reference is made to the “server” 1200, as one ofordinary skill in the art will recognize, embodiments of the presentinvention are not limited to traditionally defined server architectures.Still further, the system of embodiments of the present invention is notlimited to a single server, or similar network entity or mainframecomputer system. Other similar architectures including one or morenetwork entities operating in conjunction with one another to providethe functionality described herein may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention. For example, a mesh network of two or more personal computers(PCs), similar electronic devices, or handheld portable devices,collaborating with one another to provide the functionality describedherein in association with the server 1200 may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention.

According to various embodiments, many individual steps of a process mayor may not be carried out utilizing the computer systems and/or serversdescribed herein, and the degree of computer implementation may vary, asmay be desirable and/or beneficial for one or more particularapplications.

FIG. 5 provides an illustrative schematic representative of a mobiledevice 300 that can be used in conjunction with various embodiments ofthe present invention. Mobile devices 300 can be operated by variousparties. As shown in FIG. 5 , a mobile device 300 may include an antenna312, a transmitter 304 (e.g., radio), a receiver 306 (e.g., radio), anda processing element 308 that provides signals to and receives signalsfrom the transmitter 304 and receiver 306, respectively.

The signals provided to and received from the transmitter 304 and thereceiver 306, respectively, may include signaling data in accordancewith an air interface standard of applicable wireless systems tocommunicate with various entities, such as the server 1200, thedistributed devices 110, 120, and/or the like. In this regard, themobile device 300 may be capable of operating with one or more airinterface standards, communication protocols, modulation types, andaccess types. More particularly, the mobile device 300 may operate inaccordance with any of a number of wireless communication standards andprotocols. In a particular embodiment, the mobile device 300 may operatein accordance with multiple wireless communication standards andprotocols, such as GPRS, UMTS, CDMA2000, 1×RTT, WCDMA, TD-SCDMA, LTE,E-UTRAN, EVDO, HSPA, HSDPA, Wi-Fi, WiMAX, UWB, IR protocols, Bluetoothprotocols, USB protocols, and/or any other wireless protocol.

Via these communication standards and protocols, the mobile device 300may according to various embodiments communicate with various otherentities using concepts such as Unstructured Supplementary Service data(USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS),Dual-Tone Multi-Frequency Signaling (DTMF), and/or Subscriber IdentityModule Dialer (SIM dialer). The mobile device 300 can also downloadchanges, add-ons, and updates, for instance, to its firmware, software(e.g., including executable instructions, applications, programmodules), and operating system.

According to one embodiment, the mobile device 300 may include alocation determining device and/or functionality. For example, themobile device 300 may include a GPS module adapted to acquire, forexample, latitude, longitude, altitude, geocode, course, and/or speeddata. In one embodiment, the GPS module acquires data, sometimes knownas ephemeris data, by identifying the number of satellites in view andthe relative positions of those satellites.

The mobile device 300 may also comprise a user interface (that caninclude a display 316 coupled to a processing element 308) and/or a userinput interface (coupled to a processing element 308). The user inputinterface can comprise any of a number of devices allowing the mobiledevice 300 to receive data, such as a keypad 318 (hard or soft), a touchdisplay, voice or motion interfaces, or other input device. Inembodiments including a keypad 318, the keypad can include (or causedisplay of) the conventional numeric (0-9) and related keys (#, *), andother keys used for operating the mobile device 300 and may include afull set of alphabetic keys or set of keys that may be activated toprovide a full set of alphanumeric keys. In addition to providing input,the user input interface can be used, for example, to activate ordeactivate certain functions, such as screen savers and/or sleep modes.

The mobile device 300 can also include volatile storage or memory 322and/or non-volatile storage or memory 324, which can be embedded and/ormay be removable. For example, the non-volatile memory may be ROM, PROM,EPROM, EEPROM, flash memory, MMCs, SD memory cards, Memory Sticks,CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, and/or the like. Thevolatile memory may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDRSDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cachememory, register memory, and/or the like. The volatile and non-volatilestorage or memory can store databases, database instances, databasemapping systems, data, applications, programs, program modules, scripts,source code, object code, byte code, compiled code, interpreted code,machine code, executable instructions, and/or the like to implement thefunctions of the mobile device 300.

The mobile device 300 may also include one or more of a camera 326 and amobile application 330. The camera 326 may be configured according tovarious embodiments as an additional and/or alternative data collectionfeature, whereby one or more items may be read, stored, and/ortransmitted by the mobile device 300 via the camera. The mobileapplication 330 may further provide a feature via which various tasksmay be performed with the mobile device 300. Various configurations maybe provided, as may be desirable for one or more users of the mobiledevice 300 and the system 320 as a whole.

The invention is not limited to the above-described embodiments and manymodifications are possible within the scope of the following claims.Indeed, a person of ordinary skill in the art would be able to use theinformation contained in the preceding text to modify variousembodiments of the invention in ways that are not literally described,but are nevertheless encompassed by the attached claims, for theyaccomplish substantially the same functions to reach substantially thesame results. Therefore, it is to be understood that the invention isnot limited to the specific embodiments disclosed and that modificationsand other embodiments are intended to be included within the scope ofthe appended claims. Although specific terms are employed herein, theyare used in a generic and descriptive sense only and not for purposes oflimitation.

The invention claimed is:
 1. An additive manufacturing apparatus foradditive manufacturing of three dimensional objects by selectivelysolidifying a powder material layer by layer, the apparatus comprising:a powder distribution unit movable across a build table for applying alayer of powder material thereon; a solidification device forselectively solidifying the applied powder layer at positionscorresponding to a cross section of an object to be manufactured; and acontrol unit configured to repeat the steps of applying and selectivelysolidifying until the object is completed, wherein: the powderdistribution unit comprises a first powder distributor and a secondpowder distributor essentially in parallel with each other and extendingin a first direction, the first powder distributor and the second powderdistributor are adjustably spaced apart in a second directiontransversely to the first direction, the second direction beingessentially in parallel with a direction of movement of the powderdistribution unit over the build table, the control unit is configuredto vary a linear speed of at least one of the first powder distributorand the second powder distributor when the at least one of the firstpowder distributor and the second powder distributor is moving acrossthe build table.
 2. The additive manufacturing apparatus according toclaim 1, wherein the first powder distributor is configured to bemovable across the build table independently of the second powderdistributor.
 3. The additive manufacturing apparatus according to claim2, wherein: the first powder distributor is configured to move acrossthe build table with a first speed; and the second powder distributor isconfigured to move across the build table with a second speed.
 4. Theadditive manufacturing apparatus according to claim 1, wherein: thefirst powder distributor is configured for moving across the build tableat a first height from the build table; and the second powderdistributor is configured for moving across the build table at a secondheight from the build table.
 5. The additive manufacturing apparatusaccording to claim 1, wherein the first powder distributor has a firstshape and the second powder distributor has a second shape.
 6. Theadditive manufacturing apparatus according to claim 1, wherein the firstpowder distributor and the second powder distributor are arranged to bespaced apart with a first distance when at rest and a second distancewhen the first powder distributor and the second powder distributor aremoving.
 7. The additive manufacturing apparatus according to claim 6,wherein the second distance is larger than the first distance.
 8. Theadditive manufacturing apparatus according to claim 1, wherein the buildtable is configured to be lowered.